Guidelines for Secure and Effective Email Sending
Email providers such as Gmail and Outlook are tightening their security and filtering standards each year to reduce spam and fraudulent activities. To ensure smooth and reliable email delivery, it is essential to use your own domain name, implement proper authentication, and configure SPF, DKIM, and DMARC records correctly.
This document outlines the key steps required to ensure that emails sent from various sources such as contact forms, third-party applications, and email scripts are delivered successfully.
1. Implement Proper Email Authentication
SPF, DKIM, and DMARC
Ensure your domain has the following authentication mechanisms enabled:
- SPF (Sender Policy Framework): Specifies which servers are allowed to send email on behalf of your domain.
- DKIM (DomainKeys Identified Mail): Adds a digital signature to each email, verifying it was not altered in transit.
- DMARC (Domain-based Message Authentication, Reporting & Conformance): Provides alignment and reporting for SPF and DKIM, helping prevent domain spoofing.
Having all three records properly configured is crucial for high deliverability and avoiding spam filters.
Note: These records must be added to your domain’s DNS zone file. If you require any assistance, please contact the Support team.
2. Enable SMTP Authentication
SMTP authentication requires users to log in with a valid username and password before sending email.
Benefits:
- Prevents unauthorized users from sending email through your server
- Reduces the risk of spam, spoofing, and phishing attacks
- Ensures accountability and traceability for outgoing emails
All email-sending applications, forms, and scripts should use authenticated SMTP connections.
3. Use a Matching "FROM" Address in Scripts and Applications
To avoid authentication failures and improve deliverability:
- Ensure that the FROM address used in email scripts or third-party application settings matches the same email address used for SMTP authentication.
- Avoid using Gmail, Yahoo, Outlook, AOL, Office365 email address in the FROM field when sending emails through scripts or web application on your hosting server.
- Using a different FROM address can cause SPF, DKIM, or DMARC alignment to fail, resulting in delivery issues or emails being marked as spam.
This alignment is critical for complying with modern email provider requirements.
4. Add CAPTCHA / Human Validation
To prevent automated spam submissions from triggering outgoing emails:
- Add CAPTCHA or similar human verification to all contact or feedback forms
- Ensure third-party forms also implement human validation
- Reduce the likelihood of bots generating large volumes of unwanted emails
This step significantly decreases spam activity and improves email reputation.
5. Remove or Minimize Email Forwarders
Email forwarders can cause forwarded messages to fail SPF, DKIM, and DMARC checks because:
- The forwarding server may not be authorized in the domain’s SPF record
- DKIM signatures may break during forwarding
- DMARC alignment often fails for forwarded mail
Recommendation:
- Remove unnecessary email forwarders
- Use direct delivery or mailbox aliases instead
Following these best practices ensures reliable email delivery, safeguards your domain reputation, and prevents unauthorized use of your domain, helping avoid potential suspension of email services due to spamming activity.